Telecommunications has advanced such that there is now a vast array of services and technologies available to consumers. As services become more sophisticated, and competition more widespread, there is a natural pressure to reduce costs and improve efficiencies in the administration of a telecommunication network.
Significant costs in network administration arise any time there is a need for a so-called “truck roll”, as a service technician is dispatched to find and repair a fault in the network. As a more specific example, in wired telephone networks based on traditional copper twisted-pair, very often a problem will require the dispatching of a service technician to physically attend at the central office that services the customer, and/or the customer sites, and/or a variety of locations in between in order to find and repair the fault. Where the distance between the central office and the customer is great, the costs are often higher.
To help pinpoint the location of the fault, it is known to locate “test heads” along the path between the central office and the customer sites. Such test heads can be based on a variety of technologies, and are intended to look perform discrete metal readings along a designated pathway, with a view to identifying ground shorts, crosses and the like.
The introduction of digital subscriber line (“DSL”) to twisted-pair networks has only increased the demand for physical integrity of each twisted-pair circuit. By the same token, the digital subscriber line access module (“DSLAM”) is typically located intermediate legacy test heads and the subscriber sites, such that the DSLAM effectively filters out the signal generated by the test head and therefore interfering with the ability of the test head to provide meaningful fault identification. Legacy test heads located inside central offices are further hampered by the sheer complexity of the circuitry in the central office, as the central office itself effectively filters out signals generated by the test head.
It is known to employ more sophisticated types of test heads to address the foregoing issues, and in particular by positioning those test heads at different locations along the twisted pair circuit when performing the test. One such sophisticated type of test head are those test heads used in locating faults on DSL lines that are based on a Time Domain Reflectometer (TDR). See for example, U.S. Pat. Nos. 5,461,318 and 6,385,561, the contents of which are incorporated herein by reference. Such prior art uses of TDR can be helpful in actually providing an indication of the distance from the test head to the fault, however, it still does not provide a location of the fault, thereby requiring that a service technician trace the length of the twisted pair until the indicated distance is reached.